The objective of this program is to design a high energy density hydrogen stroage system, utilizing ECD's extensive experience in metal hydride technology. The system will be based on ECD's ability to develop novel metal hydrides that have the potential to achieve gravimetric energy density of 2.5Wh/kg and volumetric energy density of 2500 kWh/M(3), while also having good hydrogen sorption kinetics, long cycle life, resistance to poisoning and low cost. Such a H-storage system will make the PEM and other types of fuel cells viable for commercial and military applications. Our previous work on disordered, multi-component Mg-based thin film hydrides has already achieved such high value for gravimetric energy density. However, these alloys have good kinetics only above 200oC. We will now attempt to reproduce these high storage capacity alloys in bulk with minimum loss of capacity, and during Phase II, modify them to improve the kinetics at low temperatures. ECDs technological leadership in metal hydrides was recently recognized by the United States Advanced Battery Consortium (USABC) when it was awarded a contract ($18.5 million/3 years) for the development of its proprietary nickel metal hydride electric vehicle battery. Anticipated Benefits: High energy density metal hydride systems for hydrogen storage, will allow fuel cell technology to be realized for many defense and commercial applications. The knowledge acquired under the program will also be applicable to a wide range of other products such as hydrogen fueled ICE vehicles and non-CFC heating and cooling systems, resulting in economic competitiveness within the United States.